Managing Energy Costs in Municipal Government Facilities

Municipal governments are responsible for overseeing a diverse array of buildings and facilities, including large and small administrative buildings, libraries, indoor and outdoor recreation centers, schools, and wastewater treatment plants. In addition, they are typically responsible for streetlights, parking structure lights, and traffic signals. This article examines energy consumption and savings opportunities for office buildings and outdoor lighting, which represent a significant portion of controllable energy use and offer opportunities for cost-effective energy savings.

In a typical office building, lighting, heating, and cooling represent almost 70 percent of total energy use (Figure 1), making those systems the best targets for energy savings. Energy represents about 19 percent of total expenditures for the typical office building, which is a significant operational cost that deserves attention from facility management.

Average energy use data

Figure 1: Energy consumption by end use

Ventilation and computers dominate electricity end uses in municipal facilities. Heating accounts for more than 80 percent of natural gas consumption in these structures.

Streetlighting plays an important role in enhancing public safety and aesthetics. However, it can account for as much as 40 percent of a municipality’s electric bill. Converting older lighting technologies to LEDs or other advanced technologies is one way that municipalities can reduce costs while enhancing the nighttime landscape.

Quick Fixes

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“Quick fixes” (for the purposes of this section) are energy-efficiency measures that are relatively low-cost, easy to implement, proven technologies.

Turning Things Off

Turning things off seems simple, but remember that for every 1,000 kilowatt-hours (kWh) that you save by turning things off, you save $100 on your utility bill (assuming average electricity costs of 10 cents per kWh).

Computers and monitors. Computers and other electronic equipment are ubiquitous in office buildings and can contribute up to 20 percent of overall energy consumption. You can gain significant energy savings by verifying that computer power-management settings are enabled on individual computers and monitors, forcing them to enter sleep mode after a specified period of inactivity. Effective power-management settings can cut a computer’s electricity use roughly in half, saving up to $75 annually per computer. Although most computers are now shipped with some sort of power-management settings enabled, they may be disabled or made less effective by users or internal IT staff, and can often be made more rigorous to maximize energy savings. For more information, the US Environmental Protection Agency (EPA) offers detailed instructions on Energy Star’s Business Case for Power Management page. Some users may be concerned that automatic software updates will be inhibited if power-management settings are enabled. In fact, updates can automatically begin to download when the computer awakens from sleep mode.

Other office equipment and plug loads. Like computers, devices such as printers, fax machines, and coffeemakers often have energy-reduction settings that can yield substantial energy savings. Additionally, consider supplying employees with smart power strips with occupancy sensors, which are an easy way to shut off your staff’s often-forgotten energy hogs, such as personal printers, monitors, desk lamps, radios, and clocks.

Lights. Lights should be turned off when not in use, but many people forget to take this step. When properly installed, occupancy sensors and timers can perform this task for you. A no-cost option is simply to train staff to turn off lights as part of their closing procedures (you can also help by posting notices that identify the locations of light switches).

Space heaters. Space heaters are energy hogs, drawing 1 kilowatt (kW) or more of power. As a first step, plug heaters into power strips controlled by occupancy sensors (other loads such as task lights and monitors can also be plugged into the power strips). Additionally, recognize that the perceived need for individual space heating usually indicates poor HVAC system control.

Chilled-water drinking fountains and water coolers. Water fountains generally don’t need to provide ice-cold water 24 hours a day unless it’s required for health reasons. In most cases, you can turn off the cooling systems in drinking fountains. Likewise, water coolers generally don’t need to be turned on 24 hours a day. The average office water cooler consumes about 800 kWh per year. Because much of this energy stems from standby losses, a simple method of cutting energy waste is to attach a timer. Programming an office water cooler to operate for only 10 hours a day, 5 days a week, can significantly reduce its energy waste. In addition, when it’s time to replace old coolers, choosing an Energy Star–qualified model can yield large savings over standard models because they have thicker insulation, more-efficient cooling systems, and other efficiency-boosting features.

Vending machines. Refrigerated vending machines typically operate 24/7, using 2,500 to 4,400 kWh per year and adding to cooling loads in the spaces they occupy. Timers or occupancy sensors can yield substantial savings because they allow the machines to turn on only when a customer is present or when the compressor must run to maintain the product at the desired temperature.

Turning Things Down

Some equipment cannot be turned off entirely but can be turned down to save energy.

HVAC temperature setbacks. During closed hours, turn temperature settings down in heating seasons and up in cooling seasons. Programmable thermostats make temperature setbacks a reliable option.

Peripheral and back rooms. Make sure that HVAC settings in stockrooms, rarely used offices, and other peripheral rooms are at minimum settings.

Window shades and blinds. During warm weather, blinds can block direct sunlight and reduce cooling needs; in the winter, opening the blinds on south-facing windows will let in sunlight to help heat the space.

Building automation systems tuning. For office buildings that already have a building automation system (BAS) make sure that temperature setbacks are coordinated on a quarterly basis with building occupancy. Facility engineers can align the HVAC schedules in the BAS with expected occupancy to optimize energy usage. Identify buildings that are not used at night, on weekends, or for long periods of time (such as during holiday breaks), and adjust temperature settings in those locations. Also, check that HVAC systems are not set to overcool or overheat the building. For facilities with regular occupancy schedules but without a BAS, programmable thermostats can make temperature setbacks a reliable option. The benefits of installing a BAS in a facility without one are further discussed in Longer-Term Solutions.

HVAC Cleaning and Maintenance

Regularly scheduled maintenance and periodic tune-ups save energy and extend the useful life of your HVAC equipment. It’s best to create a preventive maintenance plan that includes regularly scheduled tasks such as cleaning, calibration, component replacement, and general inspections. It’s also a good idea to ensure that information on setpoints and operating schedules is readily available for reference when equipment is checked or recalibrated.

Check the economizer. Many air-conditioning systems (other than those in hot and humid climates) use a dampered vent called an economizer to reduce the need for mechanically cooled air by drawing cool outside air into the building when it’s available. If the economizer is not regularly checked, the linkage on the damper can seize up or break. An economizer stuck in the fully open position can add as much as 50 percent to a building’s annual energy bill by allowing hot air in during cooling season and cold air in during the heating season. Have a licensed technician check, clean, and lubricate your economizer about once a year, and repair it if necessary.

Check air-conditioning temperatures. With a thermometer, check the temperature of the return air going to your air conditioner and then check the temperature of the air coming out of the register that’s nearest the air-conditioning unit. If the temperature difference is less than 14° Fahrenheit (F) or more than 22°F, the refrigerant may be under- or overcharged—using more energy than is necessary. Have a licensed technician regularly inspect your air-conditioning unit.

Change the filters. Filters should be changed periodically—every one to six months, depending on the level of pollutants and dust in the indoor and outdoor air. More-frequent changes may be required when economizers are in use because outdoor air is usually dirtier than indoor air.

Check the cabinet panels. On a quarterly basis (or after filters are changed), make sure the panels to your packaged rooftop air-conditioning unit are fully attached, with all screws in place and all gaskets intact so that no air leaks out of the cabinet. Chilled-air leaks can cost $100 per rooftop unit per year in wasted energy.

Clean the condenser coils. Check the condenser coils quarterly for either man-made or natural debris that can collect in them. At the beginning and end of the cooling season, thoroughly wash the coils.

Check the airflow. Hold your hand up to the registers to ensure that there is adequate airflow. If there is little airflow, or if dirt and dust are found in the register, ask a technician inspect your unit and ductwork.

Follow a steam-trap inspection and maintenance plan. In buildings with radiant steam heat, steam traps remove water from the steam distribution system once it has cooled and condensed in radiators or other heat exchangers. Mechanical steam traps can become stuck open, which wastes heat. A single failed trap can waste more than $50 per month—and offices with steam systems can have multiple steam traps within the building.

Encourage energy-saving behavior in the workplace. There’s growing interest in workplace sustainability and engagement. Green teams, interactive energy-use kiosks, training classes, and energy competitions are emerging strategies to encourage behavioral change in the workplace. Preliminary studies show that these efforts can garner a range of savings from about 2 to 10 percent.

Longer-Term Solutions

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Longer-term solutions are energy-saving measures that require more investment of capital or longer payback periods, but often result in larger energy and cost savings. Some general ideas include:

Set a reduction goal. Setting a goal can raise the topic of energy efficiency in the minds of your staff. In one example, the local initiative Sustainable Chicago 2015 called for a 10 percent reduction in energy use in municipal buildings.

Hire a shared energy manager. Having dedicated staff with specialized knowledge and responsibilities focused on improving facility energy use can take the load off busy facility managers. Sharing an energy manager’s services can be a convenient way for municipalities with resource constraints to improve services and reduce costs.

Commissioning

Commissioning is the process of ensuring that systems are designed, installed, functionally tested, and capable of being operated and maintained according to the owner’s operational needs. Doing so can cut energy bills by 10 to 15 percent or more, and often provides a simple payback period of less than one year. When this process is applied to an existing building that hasn’t been commissioned before, it’s called retrocommissioning. When it’s applied to a building that has been commissioned before, it is called recommissioning. Recommissioning is recommended every three to five years to maintain top levels of building performance. In another type of commissioning—ongoing commissioning—monitoring equipment is left in place to allow for continuous diagnostics.

Building Automation Systems

Sometimes called energy management systems, BASs save between 5 and 15 percent of overall building energy consumption and can also improve occupant comfort. However, due to their complexity and high cost, BASs typically only become cost-effective in buildings larger than 50,000 square feet (ft2). Older or poorly maintained buildings can also benefit greatly from a BAS retrofit, sometimes yielding savings of over 30 percent. For existing barebones BAS systems, submeters and wireless controls can be added to provide more-robust information for setting baselines, benchmarking, troubleshooting, identifying areas for improvement, and evaluating performance. Recently, prices of submeters and wireless controls have dropped markedly, making them even more attractive data-acquisition tools to improve building performance.

Cloud Thermostats

“Cloud” (Internet-enabled) thermostats can offer much of the functionality, analytic abilities, and energy-saving opportunities of a BAS at a much lower cost, making them a great choice for buildings that are less than 50,000 ft2. Even better, cloud thermostats are rapidly increasing in sophistication and may also soon provide a central control point for supplementary loads such as lighting, water heating, and plug loads.

Energy Analytics Software

A growing number of companies offer both single-building and multiple-unit portfolio analysis, allowing customers to pinpoint poorly performing systems or buildings. Identifiable problems may include malfunctioning or poorly tuned HVAC systems or whole buildings that are performing at subpar levels compared to their neighbors or other buildings in a portfolio.

Indoor Lighting Measures

LED lighting. LEDs offer several advantages over conventional light sources, including high efficiency, long life, and superior control. These characteristics and falling prices have made LEDs a viable solution for a growing number of office building applications, including exit signs, task lighting, recessed downlighting, and ambient lighting.

LED troffers offer promising benefits in the right applications. Fluorescent troffers are the most common type of lighting fixture found in US commercial facilities, accounting for 50 percent of existing luminaires. The best LED troffer products outperform their fluorescent cousins, but at a first-cost premium. You can replace fluorescent troffers with new LED troffers, via LED retrofit kits, or by replacing the fluorescent tubes with tubular LED products.

When buying LED-based products, ask for performance data based on standard tests performed by accredited laboratories. When comparing LEDs to other options, be sure to include cost savings from reduced maintenance due to LEDs’ long lifetimes in the total calculation. Make sure that the LED solution will provide the quantity and quality of light you need by starting with a small test case.

Fluorescent lamps. If your facility uses T12 fluorescent lamps or commodity-grade T8 lamps, relamping with high-performance T8 lamps and electronic ballasts can reduce your lighting energy consumption by 35 percent or more. Adding specular reflectors, new lenses, and occupancy sensors or timers can double the savings. Payback periods of one to three years are common.

Lighting controls. Using energy-efficiency light sources is only one part of the process of reducing the energy used by a lighting system. A well-designed control system will provide the right amount of light where and when it’s needed, and it will cut lighting energy use by 5 to 60 percent, depending on the baseline conditions and the control strategies used. In addition, using lighting controls may qualify you for participation in utility demand-response programs. Advanced control systems can also help lighting maintenance by signaling lamp outages and monitoring usage and output levels to indicate when they fall below required levels.

Daylighting. Daylight can improve the ambience of an office and reduce the need for electric lighting. Dimming ballasts, or dimmable LED drivers, and daylighting controls can be used to reduce the amount of electric light used when daylight is present.

Outdoor Lighting Optimization

Lighting roadways and other public spaces (recreational areas, parking lots, and public transportation depots) can consume a significant portion of a municipality’s energy footprint. While it’s essential to focus on security requirements, pedestrian and traffic safety, economic development and aesthetics, many energy-efficiency opportunities are available. The options presented are generally designed to reduce energy use, costs, light pollution, and waste light while maintaining or improving light quality; however, it’s important to get detailed specifications for your facility to ensure that the technologies you’re evaluating will meet your building’s unique needs.

Reducing light levels. Parking lots are often overlit—an average of 1 foot-candle of light or less is usually sufficient. Dimming and occupancy-sensing controls can add to energy savings in parking lots.

Installing more-efficient light sources. The most common lamps used for outdoor lighting are high-intensity discharge (HID) sources—metal halide and high-pressure sodium (HPS). Fluorescent and induction lamps are also used in parking lots, but LEDs have become the most efficient alternative as their performance has improved and prices continue to decline.

LEDs can be a good choice for parking and streetlighting applications because LED fixtures perform well in the cooler conditions that are typically found outside at night, and because LEDs work better with controls than the incumbent HID products (HPS and metal halide). In field testing of bi-level LED lighting combined with occupancy sensing at a parking garage on the California State University, Sacramento campus, energy savings of 78 percent were reported between the hours of midnight and 6 a.m. due to the majority of fixtures operating in low-capacity mode. The project report, Bi-Level LED Parking Garage Luminaires (PDF), prepared by the California Lighting Technology Center, also noted 24-hour energy savings of 68 percent compared to the incumbent HPS lighting system.

The ability of LEDs to work well with controls has encouraged several companies to develop streetlight networking capabilities. For more information, check out the Northwest Energy Efficiency Alliance’s Technology and Market Assessment of Networked Outdoor Lighting Controls (PDF) report. Taking the concept a step further, some companies are partnering with municipalities or other government entities to develop systems that use networks of LED streetlights as a backbone on which to later support functions such as traffic control and public safety. Read Greentech Media’s article Will Street Lights Become the Nodes of the Networked City? to learn more.

LEDs also offer long life, which reduces the maintenance costs associated with lamp replacement, especially for streetlights that require bucket trucks or lifts to change the lamps. Plus, LEDs provide a more even light distribution and produce less light pollution and light trespass—properties that improve aesthetics and contribute to energy savings.

Advanced RTU controllers. Retrofitting existing RTUs with advanced packaged controllers improves functionality and offers potential for significant energy savings. Estimates and preliminary field-test results indicate energy savings of 20 percent to over 50 percent with a typical payback period of one to four years. Energy-saving features can include variable- or multispeed supply fan control, demand-controlled ventilation, and improved economizer control. Additional features can include demand response, remote monitoring, and fault detection and diagnostics.

Demand-controlled ventilation. For office spaces that have large swings in occupancy levels, energy can be saved by decreasing the amount of ventilation supplied by the HVAC system during low-occupancy hours. A demand-controlled ventilation (DCV) system senses the level of carbon dioxide in the return airstream, uses it as an indicator of occupancy, and decreases supply air when carbon dioxide levels are low. DCV systems are particularly applicable to variable-occupancy spaces like auditoriums, meeting rooms, and cafeterias.

Boiler retrofits. Savings from boiler retrofit projects can be significant. Newer boilers feature a variety of efficiency improvements that can justify replacing older boilers before they fail. Improvements include condensing heat exchangers, sealed combustion, electric ignition, and fan-assisted combustion. Smaller boilers are more efficient than larger ones, and grouping multiple smaller boilers not only allows staged operation of each unit at its highest efficiency point, but also provides redundancy. If a larger boiler isn’t ready to be retired, a smaller boiler can be added to serve the base heating load, reserving the larger boiler for additional heating as needed.

Reflective building roof coating. If the roof needs recoating or painting, consider white or some other highly reflective color to minimize the amount of heat the building absorbs. Cool roofs can often reduce peak cooling demand by 10 to 15 percent. For a list of suitable reflective roof coating products, visit the Energy Star Roof Products website.